Compact endoscope tip and method for constructing same

ABSTRACT

This application presents to an endoscope having a compact distal tip, and to a method for constructing same. In some embodiments one or more optical and sensing elements are mounted directly on an internal surface of a lumen within an external housing, which housing comprises an outer wall of the endoscope tip. Space saved by eliminating intervening containing elements can be used to enhance endoscope performance and/or reduce endoscope size.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/230,745, filed Sep. 4, 2008, which claims priority to U.S.Provisional Patent Application No. 60/935,891, filed Sep. 5, 2007, eachof which is incorporated by reference herein, in the entirety and forall purposes.

FIELD OF THE INVENTION

The present invention, in some embodiments thereof, relates to anendoscope and, more particularly, but not exclusively, to an endoscopehaving a compact distal tip, and to a method for constructing same.

BACKGROUND OF THE INVENTION

Endoscopes are an essential tool in minimally invasive diagnosis andsurgery. The maneuverability of an endoscope and it's suitability foraccessing small and delicate regions of the body are in part determinedby the size of the endoscope tip, which in turn is determined by thesizes of various components the tip contains. An endoscope tip maycomprise an objective lens package containing lenses and spacers in acontainer, a prism, an imaging sensor array, and a plurality of lumensfor containing fiberoptic bundles used for illumination, fortransmitting fluid used for irrigation, for insufflation, for lenscleaning, or other purposes, and/or serving as working channels fordelivering diagnostic and surgical tools to an intervention site.

U.S. Pat. No. 5,305,736 to Ito and U.S. Pat. No. 4,773,396 to Okazakidescribe exemplary endoscope tip designs according to the methods ofprior art, wherein camera and associated lenses are mounted togetherwithin an imaging housing, and that housing is placed within anendoscope tip.

Note is also taken of PCT publication WO 2006/080015, by Pinchas Gilboaentitled “Endoscope with Miniature Imaging Arrangement”, which describesanother method of mounting lenses within a tip of a flexible endoscope.

Note is also taken of U.S. Pat. No. 5,418,566 to Kameishi, whichdescribes an imaging apparatus for an endoscope, and of U.S. Pat. No.5,188,092 to White, dated Feb. 23, 1993, which describes a rigidendoscope construction.

Disclosures of all the aforementioned patents and patent applicationsare incorporated herein by reference.

SUMMARY OF THE INVENTION

Embodiments of the present invention relate to a compact endoscope tipwherein optical and other components are mounted directly into anexternal housing, thereby enabling small endoscope tip size and/orenhanced endoscope performance.

According to an aspect of some embodiments of the present inventionthere is provided an endoscope tip comprising an external housing whichcomprises an outer wall of the endoscope tip; and a lumen; and a firstoptical element mounted directly on an internal surface of the lumen.

According to some embodiments of the invention the external housing isof unitary construction.

According to some embodiments of the invention, the external housing isof split construction and is openable to provide access to an internallumen of the housing during fabrication of the endoscope tip.

According to some embodiments of the invention, the endoscope tipfurther comprises a second optical element positioned by being mountedin flush contact with the first optical element.

According to some embodiments of the invention, an initial opticalelement, a plurality of intermediate optical elements and a finaloptical element are serially positioned along a length of an internallumen of the housing, the length of internal lumen being sized andpositioned to accommodate and to align the optical elements.

According to some embodiments of the invention, the initial and finaloptical elements are attached to an internal wall of the lumen.

According to some embodiments of the invention, only the initial andfinal optical elements are attached to walls of the lumen, the pluralityof intermediate optical elements being unattached to the lumen andmaintained in place by walls of the lumen and by the initial and finalelements.

According to some embodiments of the invention, the final opticalelement is positioned against a stop within the lumen, and the firstoptical element is attached to an internal wall of the length of thelumen.

According to some embodiments of the invention, of the optical elements,only the final optical element is attached the lumen, the plurality ofintermediate optical elements being unattached to the lumen andmaintained in place by walls of the lumen and by the initial and finalelements.

According to some embodiments of the invention, the initial,intermediate, and final optical elements comprise an objective lensarray.

According to some embodiments of the invention, an optical sensor arrayis mounted directly on an internal surface of a lumen within theexternal housing

According to some embodiments of the invention, there is provided avisualization system with a plurality of components, and a lumen of thehousing comprises a shaped portion, the shaped portion being shaped toconform to a shape of a visualization system component and being sopositioned and oriented that the visualization system component isaligned with an optical axis of the visualization system when thevisualization system is installed in the housing and the component ismounted flush against the shaped portion.

According to some embodiments of the invention, the shaped portion isformed as a flat shelf surface, and the visualization system element isan optical sensor array.

According to some embodiments of the invention, the endoscope tipcomprises a plurality of shaped lumen portions, each of the shapedportions being individually shaped to conform to a shape of a one of thevisualization system components, the plurality of shaped portions beingso positioned and oriented that when each of the plurality ofvisualization system components is mounted on a selected one of theshaped lumen portions, then the visualization system components areoptically and functionally aligned with each other.

According to some embodiments of the invention, an objective lens arrayis installed within a lumen of the housing, at least somelight-transmissive elements of the array being in direct contact withwalls of the lumen.

According to some embodiments of the invention, the objective lens arraycomprises a plurality of lenses and at least one spacer.

According to some embodiments of the invention, a distal portion of afiberoptic bundle is mounted within a lumen of the housing and attacheddirectly to the housing.

According to some embodiments of the invention, the fiberoptic bundle isa coherent fiberoptic bundle.

According to an aspect of some embodiments of the present inventionthere is provided a method for manufacturing an endoscope tip,comprising:

-   -   (a) fabricating a housing which comprises at least one lumen        sized to receive at least one component of a multi-component        visualization system, the lumen comprising a portion shaped to        orient the received component with respect to an optical axis of        the visualization system; and    -   (b) installing within the housing a visualization system which        comprises a plurality of components arranged with respect to an        optical axis, where the installation process comprises mounting        at least one component in the shaped portion of the lumen,        thereby orienting the component with respect to the optical axis        of the visualization system.

According to some embodiments of the invention, the method furthercomprises mounting a series of optical elements within a lumen of thehousing by

-   -   (a) attaching a first element of the series of elements within        the lumen;    -   (b) introducing at least one additional element into the lumen        so that the introduced elements are contiguous; and    -   (c) introducing a final element into the lumen and attaching it        to the lumen.

According to some embodiments of the invention, the first and the finalelements of the optical elements are attached to the lumen, and theadditional elements are unattached.

According to some embodiments of the invention, the method furthercomprises mounting a series of optical elements within a lumen of thehousing by

-   -   (a) introducing a first element of the series of elements into        the lumen and advancing it within the lumen until it is stopped        by contact with a form established within the lumen;    -   (b) introducing at least one additional element into the lumen        so that the introduced elements are contiguous; and    -   (c) introducing a final element into the lumen and attaching it        to the lumen.

According to some embodiments of the invention, the final element of theoptical elements is attached to the lumen, and the first and theadditional elements are unattached.

According to some embodiments of the invention, the method furthercomprises attaching a light sensor array to a shelf within a lumen ofthe housing.

According to some embodiments of the invention, attaching of the lightsensor array comprises verification of alignment and focus along oneaxis only.

According to some embodiments of the invention, the housing comprises aplurality of lumen portions each sized and shaped to receive a componentof a multi-component visualization system, and wherein when a pluralityof the components are mounted in the plurality of shaped lumen portions,the components are optically aligned with one another.

According to an aspect of some embodiments of the present inventionthere is provided an endoscope tip comprising:

-   -   (a) an external housing which comprises        -   (i) an outer wall of the endoscope tip; and        -   (ii) a lumen; and    -   (b) an optical sensor array mounted directly on an internal        surface of the lumen.

According to an aspect of some embodiments of the present inventionthere is provided an endoscope tip comprising:

-   -   (a) a visualization system which comprises a plurality of        components; and    -   (b) an external housing which comprises        -   (i) an outer wall of the endoscope tip; and        -   (ii) a lumen which comprises a shaped portion, the shaped            portion being shaped to conform to a shape of a component of            the visualization system and being so positioned and            oriented that the visualization system component is aligned            with an optical axis of the visualization system when the            visualization system is installed in the housing and the            component is mounted flush against the shaped portion.

According to some embodiments of the invention the shaped portion isformed as a flat shelf surface, and the visualization system element isan optical sensor array.

According to some embodiments of the invention the endoscope tip furthercomprises a plurality of shaped lumen portions, each of the shapedportions being individually shaped to conform to a shape of a one of thevisualization system components, the plurality of shaped portions beingso positioned and oriented that when each of the plurality ofvisualization system components is mounted on a selected one of theshaped lumen portions, then the visualization system components areoptically and functionally aligned with each other.

Unless otherwise defined, all technical and/or scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which the invention pertains. Although methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of embodiments of the invention, exemplarymethods and/or materials are described below. In case of conflict, thepatent specification, including definitions, will control. In addition,the materials, methods, and examples are illustrative only and are notintended to be necessarily limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the invention are herein described, by way ofexample only, with reference to the accompanying drawings. With specificreference now to the drawings in detail, it is stressed that theparticulars shown are by way of example and for purposes of illustrativediscussion of embodiments of the invention. In this regard, thedescription taken with the drawings makes apparent to those skilled inthe art how embodiments of the invention may be practiced.

In the drawings:

FIG. 1 is a simplified schematic of a cross-sectional side view of anendoscope tip, according to an embodiment of the present invention;

FIG. 2 is a simplified schematic of a cross-sectional rear view of theendoscope tip of FIG. 1, according to an embodiment of the presentinvention;

FIG. 3 is a simplified schematic of an end view of the endoscope tip ofFIG. 1, according to an embodiment of the present invention;

FIG. 4 is a simplified schematic of a cross-sectional side view of afiberoptic endoscope, according to an embodiment of the presentinvention; and

FIG. 5 is a simplified schematic of an end view of the fiberopticendoscope of FIG. 4, according to an embodiment of the presentinvention.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

The present invention, in some embodiments thereof, relates to anendoscope and, more particularly, but not exclusively, to an endoscopehaving a compact distal tip, and to a method for constructing same.

Embodiments here presented include endoscopes having distal tips ofreduced cross-sectional size. The endoscope distal tip is a complexportion of the endoscope, having many internal parts. A tip may containa camera and associated lenses, passages for optical fibers used forilluminating tissues in the vicinity of the endoscope tip, LEDs forilluminating the work area, fluid channels for irrigation and/orinflation, and optionally one or more operating channels for deliveringtools to a treatment area.

In embodiments presented herein, reduction in cross-sectional size ofendoscope tips is accomplished by mounting optical and/or electroniccomponents directly into appropriately sized and shaped lumensmanufactured within an endoscope tip housing, eliminating (as comparedto prior art methods) various intermediary subassembly frames andcontainers and connecting and mounting surfaces.

Construction methods taught herein save space which in prior art methodsof construction is taken up by subassembly containers. Space saved bymounting components directly into a tip housing, without intermediarysubassemblies and other objects, enables making endoscopes with smallercross-sectional areas. Endoscopes with tips having smallercross-sections are more easily maneuverable within patients and are ableto access smaller internal structures of the anatomy. Alternately, spacesaved can be used to enhance endoscope performance, for example byproviding, for a same cross-sectional area as a prior-art endoscope,higher-resolution imaging sensor arrays and/or larger optical elementsand/or larger optical fibers for illumination and/or larger LEDs forillumination and/or larger lumens for fluid or instrument delivery.

Additionally, by use of methods here presented, endoscope tipconstruction is simplified, duplication of effort is avoided, andcalibration of optical components is simplified. Before explaining atleast one embodiment of the invention in detail, it is to be understoodthat the invention is not necessarily limited in its application to thedetails of construction and the arrangement of the components and/ormethods set forth in the following description and/or illustrated in thedrawings and/or the Examples. The invention is capable of otherembodiments or of being practiced or carried out in various ways.

Attention is now drawn to FIGS. 1, 2 and 3, which are simplifiedschematics of a cross-sectional side view, cross-sectional rear view andend view respectively of an endoscope tip, according to an embodiment ofthe present invention. These Figures illustrate an endoscope tipconstructed of a unitary housing within which optical and electroniccomponents are mounted directly, absent some intervening sub-assembliesusually used for holding, organizing or containing the components.

FIG. 1 shows an endoscope tip 100 which comprises an external housing150 comprising at least a portion of outer wall 158 of tip 100. Housing150 may be a unitary (undivided) component, or may have a split ordivided design enabling to open housing 150 during construction of tip100 to facilitate mounting of various components therein.

Housing 150 comprises a plurality of shaped lumens formed to accommodatevarious optical and electronic components mounted directly within thelumens. Housing 150 may be fabricated using standard electro-erosion(wire EDM and sinker EDM) and/or other standard manufacturing techniquessuitable for metallic parts or other materials. High precisionfabrication and tight tolerances are desirable for this component, butmay be achieved by use of standard and well-known machining techniquesor other methods known in the art. Casting and molding are other methodsof fabrication suitable for producing endoscope tip 100, and metal,ceramics and plastics are among the materials appropriate for thispurpose.

FIG. 1 shows an objective lens assembly 120 mounted directly within alens mounting portion 130 of appropriate shape and size formed withinhousing 150. Objective lens assembly 120 comprises one or more lenses122 and optional spacers 124. Prior art designs utilize space-takingsub-assembly elements serving only to contain and align sub-assembliessuch as lens assembly 120. Accurate design and fabrication of lensmounting portion 130 within housing 150, and accurate design andfabrication of lens and spacer components of lens assembly 120, enablesto eliminate these sub-assembly elements and to mount components of lensassembly 120 directly into mounting portion 130 (also called lumen 130)within housing 150. Direct mounting of elements of lens assembly 120 inlens mounting portion 130 of housing 150 enables to construct an opticalsystem characterized by high performance, because space that would inprior art designs be taken up by sub-assembly container elements may, inendoscope 100, be devoted to large or complex lens designs, expandedsensor arrays, and other enhancements described hereinbelow, providingsuch advantages as higher resolution, wider angle of view, and/or largeraperture for light gathering, as compared to endoscopes of similarexternal size constructed according to prior art designs.

An exemplary configuration shown in FIG. 1 comprises 3 lenses labeled122 a, 122 b, and 122 c, and 3 spacers labeled 124 a, 124 b, and 124 c.This configuration is exemplary only: other combinations of more orfewer components may be used.

Mounting of lenses and spacers directly into an outer housing 150 ofendoscope tip 100, rather than into an intermediate lens tube or framewhich must then be installed within outer housing 150, enables reductionof cross-sectional size of the endoscope tip in which camera and lensesare mounted.

In an exemplary embodiment of the invention, the diameter of endoscopetip 100 is between 0.7 mm and 7 mm, for example, between 2 and 4 mm, forexample 3.3 mm. In an exemplary embodiment of the invention lens 122 ahas a diameter between 0.25 mm and 3 mm, for example between 0.75 mm and1.5 mm, for example 1.2 mm. In an exemplary embodiment of the inventionthe smaller lenses of lens array 120 have a diameter between 0.15 mm and2 mm, for example between 0.5 mm and 1 mm, for example 0.8 mm. In anexemplary embodiment of the invention sensor array 170 might be a squarearray between 0.5 mm square and 5 mm on a side, for example between 1.2mm and 2.5 mm square, for example 2 mm on a side. If we consider as anexample an exemplary embodiment containing a square sensor array 170 2mm on a side, a lens array 120 with lenses between 1.2 mm and 0.8 mm,and an overall diameter of 3.3 mm, we may approximately estimate thatthe diameter of an endoscope tip containing these components in similararrangement but constructed according to the methods of prior art wouldbe larger by between 0.2-0.4 mm, because of the thickness ofintermediate walls used in prior art designs for containing andorganizing the internal components.

Alternatively, the space saved can be used to enhance endoscopeperformance. For example, the freed space can be used, for a givencross-section, to increase resolution of images which can be provided bya camera-based visualization mechanism by using a larger sensor array.Visualization performance can also be improved by utilizing larger ormore complex optical elements (e.g. lenses) for a given cross-sectionaltip size. Light output can be increased by utilizing larger bundles ofoptical fibers for illumination or by providing tip mounted LEDs forillumination. Fluid flow (for irrigation, suction, insufflation,lens-cleaning, etc.) can be increased by using larger diameter fluidlumens. Working channels of increased size enable to accommodate passageof larger size surgical and diagnostic instruments. These and otherimprovements are made possible by direct mounting of lens assembly 120(and other components discussed hereinbelow) directly into lumens ofhousing 150.

In a method of construction according to an embodiment of the presentinvention, individual lens and spacer components are packed within lensmounting portion 130 by positioning and circumferentially gluing (orotherwise fixing in position) a first component (e.g. lens 122 a), thenpositioning (without gluing) additional components (lenses and/orspacers) one after another, in order as required by a desired objectivelens design, along lens mounting portion 130. The components are packedsufficiently tightly so that components are contiguous one to another.Then, the final component (e.g. 1 spacer 124 c) is glued or otherwisefixed into position, thereby immobilizing all elements of lens assembly120.

In a similar and alternative process, the lumen within which lensassembly 120 is to be assembled may be provided with a ‘stop’ feature129 (e.g. a distal wall, a projection from a lateral wall, an insertedobject) which limits advancement of the first component (e.g. lens 122a) at a desired point within lumen 130. In this alternative method thefirst component is simply advanced along lumen 130 until the stopfeature prevents further movement, additional components are introducedone after another along lens mounting portion 130 in order as requiredand packed contiguously, and then a final component is glued orotherwise fixed into position, thereby immobilizing all elements of lensassembly 120.

These assembly processes are advantageous in that manufacturingaccording to these methods is faster and more convenient than gluing orotherwise attaching each element to the housing or to the adjoiningelements. It is noted however that in some cases gluing or otherwisefixing elements to each other or to housing 150 may be consideredappropriate, and is included within the scope of the invention.

Imaging sensor 170 may also be mounted directly in an interior lumen ofhousing 150 of endoscope tip 100.

Optionally, precision fabrication of internal lumen surfaces is used. Insome embodiments precision fabrication of visualization system elements(e.g. lens assembly 120, imaging sensor 170) and also of the lumensurfaces which determine the installed position of the visualizationsystem elements when those elements are mounted flush against thosesurfaces, enable production of a visualization system which requireslittle or no calibration. Precision matching of surfaces means that thatimaging sensor 170, when mounted, will be in proper alignment withobjective lens elements 120 as mounted. In some embodiments suchassemblies require no calibration on some axes and little or nocalibration on other axes. If, in the embodiment presented in FIGS. 1-3,the visualization system elements and the lumen surfaces against whichthey are mounted are fabricated with precision, the resultantvisualization system will require calibration in at most only onedimension, and in some embodiments will require no calibration at all.For example, calibration or focusing of the embodiment presented in FIG.1 may be accomplished by placing sensor 170 against upper shelf support171 (or alternatively, against a wall of the housing) and then is movedforward or backward (left or right on FIG. 1 to accomplish focusing orcalibration. No other adjustment or calibration is needed. Reduction ofthe need to calibrate the optical elements is an improvement over priorart manufacturing processes, saving time and enhancing reliability.

Additional visualization system elements may be similarly fabricated andinstalled. For example, FIG. 1 shows an optional lightpath-bendingelement 161 used to bend the light path to enable mounting sensor array170 in a space-saving position. In this exemplary embodimentlightpath-bending element 161 is implemented as an optional prism 160.Prism 160 may similarly be fabricated to precision standards and mountedon a precision-fabricated lumen wall. Prism 160 may for example be gluedonto a surface of imaging sensor 170 or glued into position within asomewhat enlarged cavity 131 which is an extension of the lumen formedby lens mounting portion 130, cavity 131 being in precise alignment withthe central optical axis formed by lens mounting portion 130. Electroniclight-sensor array 170 may similarly be glued within an additionalcavity 132 similarly provided within housing 150, as shown in FIG. 1.Alternatively, light-sensor array 170 may be mounted perpendicular tothe central axis of lens mounting portion 130, eliminating the need forprism 160.

Endoscopes often comprise light guide fiberoptic bundles used forilluminating the visual field of the endoscope. According to embodimentsof the present invention, these light guide fiberoptic bundles are alsodirectly mounted within and directly attached to housing 150, withoutouter tubes or other constraining structures containing the bundles orforming the bundles' distal ends. This construction strategy alsoenables further reduction of the cross-sectional area of the endoscopetip, or alternatively, for a given cross-sectional size, allows foraddition of more fibers in the illuminating bundle thereby enhancingvisualization performance provided by the endoscope.

In an embodiment shown in FIGS. 1 and 2, light-guiding optical fiberbundles 180 are provided and enable one to illuminate tissues and otherobjects within the field of view of lens assembly 120. Optical fiberbundles 180 are inserted directly into lumens 182 provided withinhousing 150, and may be fixed directly therein by gluing or other means.As discussed hereinabove with respect to lens mounting portion 130,lumens 182 may be produced by machining processes applied to housing150, or by various other means. Light-guide fiber bundles 180 and lumens182 are more clearly seen in FIG. 2. For clarity of the Figures, aspatial separation has been shown between bundles 180 and lumens 182,yet in practice bundles 180 may completely fill lumens 182.Additionally, lumens 190 shown in FIGS. 2 and 3 may be used to holdadditional light-guide fiber bundles providing multi-sourceillumination.

Gluing is a convenient means for fixing individual components withinhousing 150, yet other means may be used. For example, elements such asthe lenses or prisms could be press-fit into place, or optical elementshaving a metallic coating could be brazed into place. Alternatively,elements may be held in place mechanically with a capturing element.

In an optional alternate construction, one or more lumens, examples ofwhich are labeled 190 in FIGS. 2-3, may be configured as workingchannels 194 through which surgical or diagnostic tools (e.g. tool 195)may be advanced through endoscope tip 100 and into body tissues. Thus,endoscope tip 100 may comprise one or more lumens 182 comprisinglight-guiding fiberoptic bundles 180, one or more lumens 190 serving asworking channels for introduction of surgical instruments into bodytissues, both, or neither. Lumens 190 may also be configured as fluidchannels 193, enabling passage of fluids into or out of the body throughendoscope tip 100. For example, a fluid channel 193 may be used toirrigate a treatment area, thereby facilitating viewing of that area.

Attention is now drawn to FIG. 3, which is a simplified schematicproviding an end-on view of endoscope tip 100, according to anembodiment of the present invention. FIG. 3 shows a distal end ofobjective lens 120, a light-guide lumen 182 and light-guide fiber bundle180, a working channel 194, and a fluid lumen 193.

In an exemplary method of assembly, lens mounting portion 130, cavity131, upper shelf support 171 or lower shelf support 172 for sensor array170, and other internal features are first fabricated in housing 150.Lenses and intervening spacers of assembly 120 are then inserted inproper sequence into lens mounting portion 130, as described above. Oncethese optical components are properly inserted and positioned, opticaladhesive or other suitable adhesive, for example a glue which sets withexposure to ultraviolet light, or any other suitable means, can be usedto secure objective lens assembly components 120. Since gluing is aroundthe periphery of the optical elements, where light rays do not pass,standard techniques for assembly and gluing can be used. Next, animaging sensor assembly 170 is inserted into housing 150, and accuratelypositioned onto interior surface shelf 171 to achieve proper focus, asdescribed above. Imaging sensor assembly 170 may comprise any electronicimaging sensor array, and may for example be a CCD sensor array, a CMOSsensor array, or a sensor array using other electro-optical imagingtechnology.

Adhesive may be used to secure sensor assembly 170 directly to interiorsurface shelf 171. Alternatively, imaging sensor assembly 170 may bepositioned and fixed onto interior surface shelf 172. Whichever interiorsurface (e.g. shelf 171 or shelf 172) is used to mount imaging sensorarray 170, that surface should be precisely aligned with lens mountingportion 130, thereby ensuring correct positioning of all parts of thevisualization system's optical and imaging components. Light guidebundles 180 can be installed either before or after installation of lenscomponents 120 and sensor array 170, as determined by convenience withinthe assembly process.

As used herein, the term “fiberoptic endoscope” is used to refer toendoscopes wherein a coherent fiberoptic bundle is used for transmissionof an image to an optical eyepiece, as an alternative to use of anelectronic image sensor 170 to detect and electronically transmit theimage. Attention is now drawn to FIGS. 4 and 5, which are simplifiedschematics showing side cross-sectional and end views respectively of afiberoptic endoscope 200, according to an embodiment of the presentinvention.

In fiberoptic endoscope tip 200, a coherent image-guide fiberopticbundle 210 is mounted directly within housing 150, without interveningtube or container, according to an embodiment of the present invention.

As discussed above with respect to endoscope 100, direct mounting ofobjective lens components 120 and fiberoptic bundle 210 into housing 150can reduce construction complexity as compared to prior art constructiontechniques, and can save space. This saving of space can be applied toreducing cross-sectional area of the endoscope tip, or can be used toenhance performance by providing larger or more complex opticalelements. For example, space saved by direct mounting of bundle 210 intohousing 150 can be used to increase optical performance by increasingsize and/or complexity of the objective lens elements, or can be used toincrease the number of fibers in the coherent fiberoptic image bundle,thereby enhancing resolution of images.

In an exemplary embodiment of the invention, a coherent fiberoptic imagebundle such as bundle 210 is first formed in a separate manufacturingprocess external to endoscope tip 200. As is customary in fabrication ofsuch bundles, the individual fibers in the bundle are optionally fusedtogether during the fiber drawing process. In endoscope fabricationprocesses typical in prior art, the coherent fiberoptic bundle isinstalled in the endoscope with the internal fusing structure and/or anencapsulating material intact. However, according to some embodiments ofthe present invention, during the process of installing the bundle inthe endoscope the internal fusing structure which holds the individualfibers together is removed by dissolving away the fusing material exceptfor the fusing material at the ends of the bundles. During this process,to preserve coherence of the bundle, encapsulating tubes are typicallyplaced over the ends of the coherent bundle before the fusing structureis removed. In some embodiments of the present invention, theencapsulating tube over at least one end of the bundle is removed(dissolved by acid or other chemical, for example), yet leaving theinternal fusing structure of the end of the bundle intact, beforecoherent image bundle 210 is inserted into housing 150. In this manner,coherence is preserved, yet space is saved because the

Encapsulating tube positioned over the end of the bundle during bundlepreparation is not installed in the endoscope tip.

Table 1 (below) is provided to demonstrate some advantages of methods ofendoscope assembly according to embodiments of the present invention. Itis noted that Table 1 is provided for exemplary purposes only, and isnot intended to be limiting nor should Table 1 be understood asdescribing all prior art assembly process, nor all assembly processwhich are according to embodiments of the present invention. However, itmay be seen from Table 1 that construction of endoscope 100 according toembodiments presented herein generally requires fewer parts and fewermanufacturing actions than are required by endoscope tip constructionaccording to methods of prior art.

As explained in detail hereinabove, in Procedure 1 in some embodimentsof the present invention lenses and spacers comprising an objective lensarray may be mounted directly into housing 150, rather than beingmounted into a lens tube or other container.

According to processes described above, gluing of objective lens arrayelements may also be simplified as shown in Table 1 with respect toProcedure 2. Prior art procedures 5, 6, and 7 of Table 1 are madeunnecessary in some embodiments of the present invention, since in someembodiments of the present invention there is no lens tube and noimaging sensor frame, lens and sensor elements being mounted directly inhousing 150. Calibration of the assembled product also tends to besimpler in embodiments of the present invention, in that according tomethods of prior art, alignment and focus of a sensor assemblyfulfilling the role of sensor assembly 170 must take into account threeaxes of focus and alignment. In contrast, in some embodiments of thepresent invention positions and orientations relevant to the alignmentand focus of optical components with respect to sensor elements aresubstantially determined by the positioning and orientation of theinternal lumen surfaces of external housing 150, together with accurateproduction of external surfaces of elements to be installed in housing150. In consequence, in some embodiments of the present invention onlyone axis of focus is involved in methods of construction of endoscope100 according to embodiments of the present invention.

TABLE 1 Comparison of Assembly Steps for Prior Art Endoscope Tips andfor endoscope tips according to some embodiments of the presentinvention Assembly process according Assembly process according to anembodiment of the Procedure to prior art present invention 1 Insertlenses & spacers Insert lenses & spacers into Lens Tube into lensmounting portion of Endoscope Tip 2 Glue lenses & spacers in Glue lenses& spacers in place in Lens Tube place. In some Tube embodiments some ofthese elements need not be individually glued. 3 Assemble imaging sensorAssemble imaging sensor and electronics onto PCB and electronics ontoPCB 4 Mount prism onto imaging Mount prism onto imaging sensor sensor 5Attach electronics PCB assembly onto imaging sensor frame 6 Insert LensTube into Distal Tip and align and/or focus as required 7 Glue Lens Tubeinto place 8 Insert imaging sensor Insert Sensor Assembly frame intoDistal Tip into Endoscope Tip 9 Align & focus Sensor Focus SensorAssembly Assembly (3 axis (only 1 axis focus alignment/focus) required,no alignment problem) 10 _Secure Sensor Assembly Secure Sensor Assemblyin place in place

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention, which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable subcombination or as suitable in any other describedembodiment of the invention. Certain features described in the contextof various embodiments are not to be considered essential features ofthose embodiments, unless the embodiment is inoperative without thoseelements.

Although the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims.

All publications, patents and patent applications mentioned in thisspecification are herein incorporated in their entirety by referenceinto the specification, to the same extent as if each individualpublication, patent or patent application was specifically andindividually indicated to be incorporated herein by reference. Inaddition, citation or identification of any reference in thisapplication shall not be construed as an admission that such referenceis available as prior art to the present invention. To the extent thatsection headings are used, they should not be construed as necessarilylimiting.

What is claimed is:
 1. An endoscope tip comprising: an housing carryinga lens mounting portion at a distal end, said lens mounting portionconfigured as a first lumen having an internal surface therewithin,wherein the internal surface comprises an obstructive feature thatnarrows a diameter of the lens mounting portion, the housing furthercarrying at least a second lumen separate from the lens mountingportion; and an optical element assembly positioned within said lensmounting portion comprising a first component, a spacer and one or moreintermediate components arranged therebetween, said componentscomprising at least one light-transmissive element, wherein the spaceris not a lens and the spacer abuts the obstructive feature of the lensmounting portion, wherein at least said first component is affixed tosaid internal surface of said first lumen and prevents distal movementof said intermediate components, and wherein said first component andobstructive feature maintain said intermediate components fixed inposition within said lens mounting portion.
 2. The endoscope tip ofclaim 1, wherein said housing is of unitary construction.
 3. Theendoscope tip of claim 1, wherein said housing is of split constructionand is openable to provide access to said first lumen of said housingduring fabrication of said endoscope tip.
 4. The endoscope tip of claim1, wherein one of said intermediate components is positioned by beingmounted in flush contact with said first component.
 5. The endoscope tipof claim 1, wherein said first component, said one or more intermediatecomponents and said spacer are configured to be serially positionedalong a length of said lens mounting portion of said housing, saidlength of said lens mounting portion being sized and positioned toaccommodate and to align said optical element assembly.
 6. The endoscopetip of claim 5, said one or more intermediate components beingunattached to said first lumen and maintained in place by walls of saidfirst lumen and by said first component and spacer.
 7. The endoscope tipof claim 5, wherein said spacer is positioned against the obstructivefeature within said lens mounting portion, said obstructive featureconfigured to limit advancement of the spacer at a desired locationwithin the first lumen.
 8. The endoscope tip of claim 1, wherein saidfirst component, one or more intermediate components, and spacercomprise an objective lens array.
 9. The endoscope tip of claim 1,further comprising a shaped portion in said housing, said shaped portionconfigured to conform to an optical sensor array such that an opticalaxis of the optical sensor array is aligned with an optical axis of saidfirst component to reduce calibration to one axis and further whereinsaid shaped portion is formed as a flat shelf surface.
 10. The endoscopeof claim 1, further comprising an objective lens array installed withina first lumen of said housing, wherein the array includes the at leastone light-transmissive element.
 11. The endoscope tip of claim 1,wherein a distal portion of a fiberoptic bundle is mounted within one ofsaid at least a second lumen of said housing and attached directly tosaid housing.
 12. The endoscope tip of claim 11, wherein said fiberopticbundle is a coherent fiberoptic bundle.
 13. The endoscope tip of claim1, wherein said first component is mounted directly into the first lumenwithout intermediary subassembly frames.
 14. The endoscope tip of claim1, wherein the endoscope tip is constructed of a unitary housing withinwhich an electronic component is mounted directly, absent interveningsub-assemblies for containing said electronic component.
 15. Theendoscope tip of claim 1, wherein said housing is unitary and said firstlumen is configured to accommodate said first component, and said firstcomponent is mounted directly within said first shaped lumen without anadditional intervening component lens tube or container housing saidfirst component.
 16. The endoscope tip according to claim 1, whereinsaid first component comprises an optical lens.
 17. The endoscope tipaccording to claim 1, wherein said at least a second lumen includes asecond lumen having an internal surface configured to receive an opticalfiber bundle and a third lumen having an internal surface configured toreceive an imaging sensor assembly directly mounted on said internalsurface of said third lumen.
 18. The endoscope tip according to claim 1,wherein an optical sensor array is mounted directly on an internalsurface of said at least a second lumen, wherein said optical sensorarray is mounted parallel to an axis of said first component.
 19. Theendoscope tip according to claim 1, further comprising a fiberopticbundle.
 20. An endoscope tip comprising: a housing including acylindrically shaped cavity and a lens mounting portion, the lensmounting portion defining a first lumen, said first lumen comprising awall having an internal surface and an surface, said internal surfacecomprising an obstructive feature configured as a projection to narrowthe diameter of the lens mounting portion and said surface comprising anouter wall of said endoscope tip; wherein said cavity comprises a wallhaving an internal surface and an surface, and is configured as aproximal extension of the first lumen such that the surface of the wallof the cavity is coextensive with the surface of the wall of the firstlumen; and a prism is mounted to the internal surface of the wall of thecavity; an optical assembly including a first component, a finalcomponent and a plurality of intermediate components, said componentscomprising at least one light-transmissive element and at least onespacer in direct contact with the internal surface of the wall of thelens mounting portion, wherein said final component abuts theobstructive feature of the lens mounting portion and prevents proximalmovement of the components, wherein said first component is affixed tosaid internal surface of said lens mounting portion and said pluralityof intermediate components are positioned serially within said lensmounting portion by said first and final components; and at least asecond lumen.